Movable jaw wrench and hydraulically controlled stop device therefor



Jan. 22, MOIR MOVABLE JAW WRENCH AND HYDRAULICALLY CONTROLLED STOP DEVICE THEREFOR Filed Feb. 19, 1953 FIGI INVENTOR JOHN MOIR ATTORNEYS MOVABLE JAW WRENCH AND HYDRAULICALLY CONTROLLED STOP DEVICE THEREFOR John Muir, Minneapolis, Minn.

Application February 19, 1953, Serial No. 337,730

2 Claims. (Cl. 81-84) The herein disclosed invention relates to wrenches and has for an object to provide a wrench having a body with a fixed jaw and a movable jaw and in providing a fluid controlled stop device for limiting the movement of the fixed jaw away from the movable jaw.

An object of the invention resides in constructing the stop device with a cylinder having a piston therein and to which is connected a piston rod, said piston dividing the cylinder into a pressure chamber and storage chamber containing a liquid, and in further bringing the chambers into communication and controlling the flow of liquid from the pressure chamber to the storage chamber.

Another object of the invention resides in providing an overflow chamber in which the liquid displaced by the piston rod may be discharged.

A feature of the invention resides in providing in said overflow chamber a collapsible vessel having a gas therein and serving to compensate for the differences in the sums of the volumes of said pressure and storage chamber caused by the volume displaced by the piston rod.

An object of the invention resides in disposing the overflow chamber at the end of the cylinder at which the pressure chamber is disposed and in providing a passageway connecting the pressure chamber and the overflow chamber and in further providing a passageway connecting the overflow chamber and the storage chamber.

Another object of the invention resides in disposing said valve in said first named passageway.

A feature of the invention resides in providing a laterally disposed actuator for the valve.

Other objects or" the invention reside in the novel combination and arrangement of parts and in the details of construction hereinafter illustrated and/ or described.

In the drawings:

Fig. l is an elevational view, partly in section, illustrating an embodiment of the invention and taken on line 11 of Fig. 2.

Fig. 2 is a cross sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a view of the cylinder of the wrench and illustrating another form of the invention.

In the drawings has been shown a wrench having a body elongated in form constructed with a head having a fixed jaw secured thereto and a shank extending from the head and forming a guide. in conjunction with the fixed jaw is a movable jaw pivoted to the body of the wrench and actuated by means of a toggle linkage including a lever and a link slidable along said guide. The link of the toggle linkage is limited in movement by stop means carried by the shank of the wrench so that the lever thereof may be brought into alignment with said link to exert maximum pressure on the jaws. The stop device forming the principal feature of the invention consists of a cylinder having a bore therein and in which is a slidable piston having a piston rod connected thereto and extending outwardly beyond the cylinder, said piston 7 rod being movable in said guide. This piston rod engages the link of the toggle linkage and forms a reaction retogether.

2,778,259 Patented Jan. 22, 1957 straining movement in a direction of opening of the movable jaw. The piston divides the cylinder into a pressure chamber and a storage chamber. In addition, an overflow chamber is provided in the cylinder which is situated at the end of the cylinder adjacent the pressure chamber and which is in communication therewith through a passageway formed in the cylinder. The said overflow chamber is further in communication with the storage chamber through another passageway. In the first named passageway is disposed a manually controlled valve which closes communication with the pressure chamber and which is operated by a laterally extending actuator. In the overflow chamber is mounted a collapsible vessel constructed of resilient material and containing a gas,'

said vessel serving to compensate for the diflerences in the sums of the volumes of said pressure and storage chambers caused by the volume displaced by the piston rod when the same is moved. Within the chambers and passageways is disposed a liquid. The collapsible vessel is normally compressed to maintain pressure within the chambers and passageways at all time to exclude air from entering said passageways.

For the purpose of illustrating the invention a wrench has been shown which consists of a body 10 constructed of sheet metal. This body is U-shaped in form and is provided with spaced flanges ill and a web 12 therebetween. The wrench is so constructed that the upper end of the same forms a head 13 and the lower end a shank l4. Welded to the head 13 is a fixed jaw 15 which is angularly disposed with reference to the direction of extent of the body. Disposed between the flanges l1 and pivoted thereto by means of a pintle 16 is a lever 17. This lever has attached to it a movable jaw 18 which, as the lever swings about its pivot, is movable from and towards the fixed jaw 15. The lever 17 is moved by means of a toggle linkage 19 which includes a lever 21 and a link 22. The lever 22 is constructed of sheet metal which is bent U-shaped in form to provide flanges 25 and a web 26 therebetween. Lever 21 has an arm 23. This arm has the web 26 thereof cut back as indicated at 27 so that the flanges 25 thereof may straddle the lever 17. A pintle 24 extending through said flanges and the lever serve to pivot the two levers One end of the link 22 is received between the flanges 25 of lever 19 and is pivoted thereto by means of a pintle 28 which extends through said flanges and link. This pintle is disposed intermediate the ends of the lever 19 so that another arm 29 is provided and which serves as a handle for manipulating the toggle linkage. The other end 31 of the link 22 is received between the flanges 11 of the body 10 and is slidable in a guideway 32 formed in the shank 14 of the body It). This guideway is substantially circular in form and is provided with a slot 33 at the inward portion of the same. A short pin 34 extends outwardly from the link 22 on both sides thereof and engages the walls of the guideway 32 and restrains movement of the end 34 of the link out of said guideway.

The invention proper consists of a cylinder 35 which is formed with a bore 36 therein. Slidably mounted in the bore 36 is a piston 37 having a piston head 38 with a cup leather 39 secured thereto. The bore 36 terminates short of the end of the cylinder 35. Formed in the cylinder 35 is a passageway 41 which is of smaller dimensions than the bore of the cylinder to provide a shoulder 42 between said passageway and bore. Resting on this shoulder is a washer 44 which has a hole 45 in the center of the same. Seated against this washer is a compression coil spring 43 which also engages the piston 38 and urges the same outwardly as shown in Fig. 1. The passageway 41 has a reduced portion 45 which forms therewith a conical shoulder 46 serving as a valve seat. In the passageway 41 is provided a valve head 47 which seats against the seat 46 and which is urged into position by means of a compression spring 48 seated against the head 47 and against the washer 44. The valve head 47 has issuing from it a valve stem 49 which is square in cross section and which is guided for movement in the reduced portion 45 of passageway 41. Intersecting the reduced portion 45 of passageway 41 is a transverse bore 51 which is open at the right-hand end as viewed in Fig. 3 and closed at .its other end. In this bore is slida-biy mounted a rod 52 which serves as an actuator for unseating the valve head 47 and opening the valve. This actuator has a cylindrical plunger 53 which slides along the bore 51 and guides the actuator 52 for movement in said bore. The other end of the rod forming the actuator 52 is guided for movement in a bearing 54 which is provided with a seal 55. The rod 52 has a cam 56 which is adapted to engage the extreme end 58 of the stem 49 of the valve head 47. A button 57 on the end of the rod 52 serves as an operating member for operating said actuator and when pressed inwardly causes the cam to raise the valve stem 49 and unseat the valve head 47 from its seat 46.

The piston 37 divides the bore 36 into two chambers 60 and 61 of which the chamber 60 will be referred to as a storage chamber and the chamber 61 as a pressure chamber. In the lower end of the cylinder 35 is formed an overflow chamber 62. A passageway 63 communicates with said chamber and with the bore 51. Passagcway 63 also communicates through a passageway 64 with the chamber 69. In this manner both of the chambers 60 and 62 are always in communication. Screwed to the lower end of the cylinder 35 is a cap 65 which has attached to it a metallic bellows 66. This cap has a vent '70 in the same and which communicates with the interior of the said bellows.

A piston 36 has attached to it a piston rod 67 which passes through a cap 68 secured to the upper end of the cylinder 35. This cap has a threaded stem 69 which screws into threads 71 formed on the shank 14 of the body of the wrench. The said stem and cap are formed with a bore 75 in which the piston rod 67 is slidable. The piston rod 67 has a head 72 secured to the same which is slidably mounted in the guideway 32. This head is directly engaged by the end 31 of the link 22. A seal 73 encircling the piston rod 67 prevents leakage past the cap 68 and a gasket 74 disposed between said cap and cylinder prevents leakage between the cap and cylinder.

The operation of the invention is as follows: When the handle 29 is pulled outwardly jaw 18 is moved away from jaw and the wrench is open. While handle 29 is moving outwardly spring 43 is urging the piston 37 upwardly and maintains the head 72 in engagement with the end 3'1 of link 22. During such movement of the piston suction in the pressure chamber 61 opens the valve head v 47 and allows liquid within the interior of the cylinder to be drawn from chambers 60 and .62 into the chamber 61. Upon pressing the button 57 valve head 47 is unseated and pressure on the handle 29 closes the movable jaw 18 toward closing position and further moves the piston rod 67 and piston 37 downwardly. During such movement liquid is being discharged from chamber-61 into passageway 51. From this passageway the liquid flows into passageway 63 and from which part of it enters into chamber 60 and the balance into chamber 62. Due to the fact that the piston rod 67 displaces an appreciable amount of space in the chamber 60, less liquid is received in this chamber than is discharged from chamber 61. This causes the liquid to compress and to collapse the bellows 66 in chamber 62. The said bellows is of such dimensions as to receive the overflow from chamber 60 when the piston is moved to its lowermost position. When the lever 21 and the link 22 are almost in alignment the button 57 is released and spring '76 urges the cam 56 away from stem 49 and spring 48 closes the valve head 47.

Further pressure on the lever 21 produces no movement of the piston rod 67 which serves as a stop and all further movement is taken up in the stressing of the work being clamped and the stressing of the parts of the wrench. The wrench may now be used in the conventional manner.

in Fig. 3 a modification of the invention has been shown. This form of the invention is quite similar to that shown in Fig. l, and the description of the corresponding parts will not be repeated. In this case the same reference numerals preceded by the digit 1 will be used to designate the corresponding parts.

In the modification of the invention shown in Fig. 3 a neoprene capsule 77 has been used in place of the bellows 66 and which has a chamber 78 within the same filled with air. This capsule is compressed the same as the bellows and operates in the same way to collapse and permit the overflow to enter the chamber 162.

In the device shown in Fig. 3 a diaphragm 79 is ,substituted for the O-ring 73 of the other form of the invention. This diaphragm is clamped in between the cap 168 and the cylinder and is bonded to a sleeve 81 secured to the piston rod 167. This diaphragm is movable with the piston rod and is capable of movement to the full extent of the movement of said rod and the piston 137. A similar diaphragm 82 is used to control the movement of the actuator 52. Both of these diaphragms prevent absolute leakage of air into the device or oil from the same. This form of the invention operates in the same manner as that previously described.

The advantages of the invention are manifest. The wrench is quickly adjusted to position of use without the necessity of rotating threaded members. The stop device of the invention operates positively and forms a dead stop for the end of the link of the toggle linkage. By use of the metallic bellows or the collapsible capsule the surplus oil is received in the overflow chamber and at the same time .a small pressure maintained at all times throughout the entire device. Leakage past the piston and into the storage chamber is of no consequence since the storage chamber does not communicate with the exterior. Leakage out of the device is prevented by maintaining the interior of the device at a low pressure and by means of the seals used for the purpose. The device can be constructed at a nominal expense and can be applied to existing wrenches of the type illustrated by merely removing the adjusting screw and substituting the instant invention. The cylinder of the invention forms an excellent handle for the manipulation of the wrench.

Changes in the specific form of the invention, as herein described, may be made within the scope of what is claimed without departing from the spirit of the invention.

Having described the invention, what is claimed as new and desired to be protected by Letters Patent is:

1. In a hydrostatically controlled stop or abutment means a cylinder having a bore therein, and end walls at the ends of the bore, a piston slidable in said bore, a piston rod connected at one end to said piston and passing through one of said end walls, the other end of said piston rod forming a stop, said piston dividing said bore into a pressure chamber and a storage chamber, one on each side thereof, means including a passageway for bringing said chambers into communication, a manually con trolled valve in said passageway, a liquid disposed in and completely filling said chambers and passageway and means communicating with said storage chamber and controlling the pressure therein and maintaining at all times a super-atmospheric pressure therein.

2. In a hydrostatically controlled stop or abutment means a cylinder having a bore therein, and end walls at the ends of the bore, a piston slidable in said here, a piston rod connected atone end to said piston and passing through one of said-end walls, the other end of said piston rod forming a stop, said piston dividing said bore into a storage chamber at the end of the same in which the connecting rod is disposed and a pressure chamber at the other end thereof, said body having a surplus chamber disposed adjacent said pressure chamber, said body having a passageway communicating with said surplus chamber and said storage chamber, said body having a second passageway communicating with said pressure chamber and said surplus chamber, a collapsible vessel subject to the pressure in said storage chamber, a liquid disposed in and completely filling said chambers and passageways and adapted to compress said expansible chamber upon increase in pressure in said storage and surplus chambers and a manually controlled valve in said second named passageway adapted to obstruct the flow of References Cited in the file of this patent liquid from said pressure chamber and into said storage 15 2,628,692

chamber.

UNITED STATES PATENTS Irland July 7, Weeks Nov. 17, Wilson June 1, Christensen Oct. 25, Davis Nov. 12, Petersen Apr. 14, Kvapil Mar. 9, Steckelberg Nov. 8, Hoover et al. Mar. 14, Manspeaker Nov. 21, Jones Apr. 15, Hufferd Feb. 17, 

